A stethoscope is an acoustic device used largely, though not exclusively, by medical practitioners to listen to internal sounds of the human body, thus aiding in the diagnosis of certain diseases and conditions. It is most commonly used to hear sounds generated by the heart and lungs, but is sometimes used to listen to the stomach and intestines, blood flowing in arteries and veins, and also to developing fetuses in pregnant women.
A binaural stethoscope consists of a chest piece connected to Y-shaped flexible tubing which terminates into two ear pieces. The chest piece is placed on the region of the body requiring auscultation by the physician.
The chest piece often is composed of a diaphragm that vibrates as a result of body sounds, creating acoustic pressure waves, which are conducted through the air-filled tubing to the ear pieces where they are received and interpreted by the practitioner. Some stethoscopes have a chest piece that is two-sided, with a diaphragm on one side, and a bell or hollow cup shape on the opposite side. The diaphragm is better adapted for transmission of higher frequency sounds, while the bell is better adapted for low frequency transmissions.
Electronic stethoscopes, with a transducer and amplifier in the chestpiece are available as well, and these are used in the same manner as traditional stethoscopes, with the chestpiece placed directly on the skin of the patient, or occasionally on the patient's clothing.
A serious concern among medical practitioners is the occurrence, within 48 hours of admittance to a hospital or within 30 days of discharge, of an infection secondary to the patient's original condition. Nosocomial (hospital-acquired) infections, such as Staphylococcus aureus (including Methicillin-resistant Staphylococcus aureus [MRSA]), Pseudomonas aeruginosa, Clostridium difficile, and Acinetobacter baumanni, are estimated to affect one hospital patient in ten, contribute to the death of many of those patients, prolong hospitalization and increase health care costs. It is also estimated that one-third of all nosocomial infections may be prevented.
There are numerous vehicles for the spread of microorganisms, including airborne propagation, transmission through sources of food and water, and of course, physical transmission through direct surface-to-body contact, particularly during care-giving activities. Transmission can be significantly reduced by the use of physical barriers to transmission, such as gloves, equipment coverings, and drapes. Removal of disease-causing materials through handwashing and cleaning of equipment is also highly effective in reducing infection transmission.
Disposable gloves greatly increase the safety of interactions during patient contacts, by providing a clean surface for each patient. Similar contact occurs when doctors, nurses, and other health care providers utilize a stethoscope and moves from patient to patient to accomplish physical examinations, monitor patients' blood pressure, or during clinical emergencies.
Studies have shown that a stethoscope's diaphragm and bell can harbor pathogenic agents, leading many medical personnel to routinely swab those areas with isopropyl alcohol between patient contacts. Despite its necessity, this routine is understandably inconvenient and has precipitated development of sanitary stethoscope covers, so that the instrument can be covered with a disposable cover
Stethoscope covers have been designed to protect soiling of the stethoscope, provide decoration, and enhance comfort to the patient.
A number of inventions have attempted to create highly functional hygienic stethoscope covers, but all have fallen short of providing the caregiver with the high level of convenience and ease of use desired, while maintaining the instrument's sound transmission capability.